The Tanzanian Mountain Ball is a tough 100% natural rubber ball infused with vanilla extract. The medium is great for medium and large breeds. The small ball is ideal for for small to medium breeds. It has deep flexible ridges designed for maximum grip. It has deep flexible ridges designed for maximum grip and the ridges can be stuffed with treats or peanut butter to make an interactive toy. This durable ball has a powerful bounce, great for games of fetch! Both sizes come in varying colour.